m-(carbamoyloxy)-carbanilates as herbicides



United States Patent is the radical of a primary or secondary amine of the 3,404,975 formula m-(CARBAMOYLOXY)-CARBANILATES AS HERBICIDES 5 Kenneth R. Wilson, Lockport, and Kenneth L. Hill, Mid- I dleport, N. Y., assignors to FMC Corporation, New York, N.Y., a corporation of Delaware HN No Drawing. Continuation-impart of application Ser. No. 419,559, Dec. 18, 1964. This application Nov. 15, 1965, R0

Ser. No. 507,713 D 7 v 25 C m is the radical of a m-aminophenol of the formula on ABSTRACT OF THE DISCLOSURE I Herbicidal compositions containing m-(carbamoyloXy)-carbanilates. v NH it, This application is a continuation-in-part of applicaand X is oxygen Sulfur- The subfitufmts 13B and tion $61. No. 419,559, filed Dec. 18, 1964, now abanmay also m together a heterocychc g wlth the doned V rogen to 'WhlCh they are attached, e.g. a morpholine or This invention relates to novel herbicidal compounds, Plpendlne COIIIPOIIIIdto new herbicidal compositions and to a new method for In one useful class of compounds, A is an ahphatlc the control of undesired plant growth, both pre-emerhydrocarbon radical, such as an alkyl, allrenyl, or alkynyl gently and post-emergently, by application of said new f i such as methyl ethyl, propyl, lsopropyl, butyl, and useful herbicidal compositions. I lsobutyl, tert-butyl, sec-butyl, p y y p py y The novel compounds of this invention are m-(carb- Y Y ZPbUTeHYI P PY W 3 -P amoyloxy)carbanilates of the following structure: PY Y fadlcal- Compounds having a cycllc RA p; 9%- O R cyclohexyl, cyclopropyl, phenyl, or a group contammg g B atoms other than carbon and hydrogen, e.g. a methoxyethyl group, may also be used. Preferably, R is an alkyl RC or alkenyl radical of relatively low molecular weight; thus, when X is oxygen, best results are obtained when R has less than six carbon atoms, preferably less than I five carbon atoms, while when X is sulfur there are pref- RD erably less than three carbon atoms, so that in one preferred class R X has a molecular weight less than 74. wherein R is the radioal of an alcohol or phenol of the In the preferred types of the compounds of this invenformula R OH, tion, R is hydrocarbon radical and R is hydrogen or a RB 40 hydrocarbon radical: Examples of such hydrocarbon radicals are alkyl radicals, such as methyl, ethyl, propyl, N isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, pentyl,

RC neopentyl, l-methylbutyl, isopentyl, hexyl, 1,1,3,3-tetra- 0 0H o-ii-NHRB NHRD N-(IT-XRA n O O l R Noo I O R NH RAX*-(%CI RnNH( JCl I i on ONa o-ri-m Neil 01:00 N(F:;-XRA II\T%-XRA IIT("3XRA D 0 RD 0 RD 0 R3 0 R]; I ya, 1,

Rc RC i RB O-CN methylbutyl, alkenyl radicals such as allyl, 2-methylallyl,

2 b'utenyl, I ethylallyl, cycloaliphatic radicals'sucl'i "as cyclohexyl or cyclopropyl, and aromatic radicals such as phenyl or tolyl. Compounds in which there are additional elements (e.g. chlorine or oxygen, as in 2-chloroethyl or Z-methoxyethyl) besides carbon and hydrogen in. the R or R radicals are also within the broad scope of this invention. In a class which is particularly preferred because of its high herbicidal effectiveness, the R and R substituents are relatively short, e.g. the sum of the lengths of the longest straight chain (or single carbon) of the R substituent, and the longest straight chain (or single carbon) of the R substituent is about 4 carbon atoms or less.

R is preferably hydrogen or a methyl group.

The novel compounds of this invention may be prepared by methods employed for syntheses of carbamic and carbanilic acid esters. For example, a very useful series of reactions was outlined previously.

The intermediate m-hydroxycarbanilic acid esters may be prepared by treatment of m-aminophenol or a N- rnonosubstituted-m-aminophenol with the appropriate chloroformate, or chlorothioformate ester in the presence of a suitable acid acceptor.

The reaction of an isocyanate with an appropriate mhydroxycarbanilic acid ester to give the corresponding monosubstituted-carbamate ester may be catalyzed by materials such as triethylarnine, 1,4-diazabicyclo[2.2.2]- octane, dibutyltin diacetate, dimethyltin dichloride and dibutylbis(dodecylthio)tin.

Reaction of the sodium salt of a m-hydroxycarbanilic acid ester with a N-monosubstitutedor a N,N-disubstituted-carbamoyl halide will produce the corresponding m-[ (N-monosubstitutedor N,N-disubstituted-carbamoyl) oxy] carbanilic acid ester. The same products may be obtained by first treating the sodium salt of a m-hydroxycarbanilic acid ester with phosgene to form the chloroformate ester, and reaction of this compound with a primary or secondary amine. The intermediate sodium salt of the m-hydroxycarbanilic acid ester is formed in an non-aqueous solvent, using a reagent such as sodium hydride, to avoid hydrolysis of the ester linkage.

Another series of reactions useful for the preparation The intermediate m-nitrophenyl carbamates are obtained by reaction of rri-nitrophenol 'with an appropriate isocyanate, or by reaction of the sodium salt of m-nitrophenol with an N-monosubstitutedor a N,N-disubstituted-carbamoyl halide. They may also be prepared by conversion of m-nitrophenol to its chloroformate ester with phosgene, and reaction of this ester with a primary or secondary amine. These m-nitrophenyl carbamates are readily reduced to the corresponding m-aminophenyl carbamates,

Treatment of the m-aminophenyl N-monosubstitutedor N,'N-disubstituted-carbamate with an appropriate chloroformate, or chlorothioformate ester, in the presence of a suitable acid acceptor, will give the desired m-[(N- monosubstitutedor N',N-'disubstituted-carbamoyl)oxy] carbanilate, ester. Formation of the possible by-product, a urylenediphenylene biscarbamate, is minimized by slow addition of the m-aminophenyl carbamate to a solution of the chloroformate ester, so that the latter is always present in a large excess.

Other methods useful for the preparation of m-[(N- substitutedcarbam0yl)oxy] carbanilic acid esters include the reaction of a m-hydroxycarbanilic acid ester with an alkyl N-substituted-carbamate of a N-substituted-urea. The reaction may be driven to completion by removal of the volatile alcohol or ammonia formed. Similarly, reaction of an alkyl carbonate ester of the m-hydroxycarbanilate with a primary or secondary amine will yield the desired carbamate and an alcohol. Removal of this alcohol wil force the reaction to completion.

These reactions of amines with chloroformate esters and of phenols with phosgene, isocyanates, carbamoyl halides and the other reagents described hereinabove are well known in the art. For example, useful procedures for the preparation of carbamic acid and carbanilic acid esters are described by R. B. Wagner and H. D. Zook, Synthetic Organic Chemistry, Chap. 23, John Wiley and Sons, Inc., New York, 1953.

Obviously the reactants selected will depend on the final product desired, as will the choice of synthetic procedures used. The m-(carbamoyloxy) carbanilate esters thus produced are novel compounds, and the characterized by excellent herbicidal properties.

oxy)-carbanilate esters as above defined are formulated into herbicidal compositions, by admixture, in herbicidally effective amounts, with the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural applications, recognizing the fact that the formulation and mode of application of a toxicant may effect the activity of the material in a given application. Thus, these active herbicidal compounds may be formulated as granules of relatively large particle size, as wettable powders, as emulsifiable concentrates, as powdery dusts, as solutions, or as any of several other known types of formulations, depending on the desired mode of application. Preferred formulations for both preand post-emergence herbicidal applications are wettable powders, emulsifiable concentrates, and granules. These formulations may contain as little as 0.5% to as much as 95% or more by weight of active ingredient.

Wettablepowders are in the form of finely divided particles which disperse readily in water or other dispersant. The wettable powder is ultimately applied to the soil either as a dry dust or as a dispersion in water or other liquid. Typical carriers for wettable powders include fullers earth, kaolin clays, silicas and other readily wet organic or inorganic diluents. Wettable powders normally are prepared to contain about 5-95% of active ingredient by weight and usually also contain a small amount of wetting, dispersing or emulsifying agent to facilitate wetting and dispersion. For example, a useful wettable powder formulation contains 80.8 parts by weight of the m-(carbamoyloxy) carbanilate ester, 17.9 parts by weight of palmetto clay, and 1.0 part by weight of sodium lignosulfonate and 0.3 part by weight of sulfonated aliphatic polyester as wetting agents.

Emulsifiable concentrates are homogeneous liquid compositions which are dispersible in water or other dispersant, and may consist entirely of the m-(carbamoyloxy)- carbanilate ester with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthas, isophorone and other non-volatile organic solvents. For herbicidal application these concentrates are dispersed in water or other liquid carrier, and normally applied as a spray to the area to be treated. The percentage by weight of the essential active ingredient may vary according to the manner in which the composition is to be applied, but in general comprises 0.5 to 95% of active ingredient by weight of the herbicidal composition. For example, a useful emulsifiable concentrate formulation contains 11.6 parts by weight of the m-(carbamoyloxy)carbanilate ester, 57.7 parts by weight of cresol, and 30.7 parts by weight of sulfated ethoxylated nonylphenol.

Granular formulations, wherein the toxicant is carried on relatively coarse particles, are usually applied without dilution to the area in which suppression of vegetation is desired. Typical carriers for granular formulations in clude sand, fullers earth, bentonite clays, vermiculite, perlite and other organic or inorganic materials which absorb or which may be coated with the toxicant. Granular formulations normally are prepared to contain about 5-25% of active ingredient and may also contain small amounts of other ingredients which may include surface-active agents such as wetting agents, dispersing agents or emulsifiers; oils such as heavy aromatic naphthas, kerosene or other petroleum fractions, or vegetable oils; and/or stickers such as dextrins, glue or synthetic resins. The average particle size of the granules is usually between 150 and 2400 microns. For example, a useful granular formulation contains 5.05 parts by weight of the m-(carbamoyloxy)carbanilate ester, 5.00 parts by weight of corn oil, and 89.95 parts by weight of crushed corn cobs.

Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; polyhydric alcohols; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used, normally comprises from 0.1% to 15% by weight of the herbicidal composition.

Dusts, which are free-flowing admixtures of the active ingredient with finely divided solids such as talc, clays, flours, and other organic and inorganic solids which act as dispersants and carriers for the toxicant, are useful formulations for soil-incorporated applications; the finely divided solids have an average particle size of less than about 50 microns.

Pastes, which are homogeneous suspensions of a finely divided solid toxicant in a liquid carrier such as water or oil, are employed for specific purposes. These formulations normally contain about 595% of active ingredient by weight, and may also contain small amounts of a wetting, dispersing or emulsifying agent to facilitate dispersion. For application, the pastes are normally diluted and applied as a spray to the area to be affected.

Other useful formulations for herbicidal applications include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene or other organic solvents. Pressurized sprays, typically aerosols wherein the active ingredient is dispersed in finely divided form as a result of vaporization of a low boiling dispersant solvent carrier, such as the Freons, may also be used.

The preparation, properties, and herbicidal activity of representaitve compounds of this invention are illustrated further in the following examples, in which all temperatures are in degrees centigrade.

Example 1.Methyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate methyl m-hydroxycarbanilate was prepared as follows: To a solution of 43.6 g. of m-aminophenol in 250 ml. of dry acetonitrile was added 18.9 g. of methyl chloroformate at a rate which maintained the temperature of the solution below 40. The resultant mixture was stirred for one hour at room temperature and for two hours at reflux temperature, then cooled. The precipitate of m-aminophenol hydrochloride was removed by filtration and the filtrate was evaporated to dryness. The crude product was recrystallized from water to yield 11.0 g. of methyl m'hydroxycarbanilate melting at 94-6".

This product was reacted with methyl isocyanate as follows: To a stirred solution of 5.5 g. of methyl mhydroxycarbanilate and two drops of triethylamine in 75 ml. of ether, 2.3 g. of methyl isocyanate was added dropwise. The mixtures was stirred and refluxed for 18 hours and cooled. The white crystalline product was isolated by filtration. A yield of 4.5 g. of methyl m-[(-methylcarbarnoyl)oxy]carbanilate, melting at -2", was obtained. On recrystallization from toluene, this ester melted at 131.

Analysis.-Calculated for C H N O C, 53.56; H, 5.39; N, 12.49. Found: C, 53.80; H, 5.57; N, 12.45.

The pre-emergence herbicidal activity of methyl m- [(methylcarbamyl)oxy]carbanilate was demonstrated as follows: In flat pans was placed, to a depth of three inches, a 1:1 mixture of silt loam and sandy loam soil. In the soil were then planted seeds of crabgrass (Digitari sanguinalis), German hay millet (Setaria italica), yellow foxtail (Setaria glaucw), flax (Linum usitaltissim'um) mustard (Brasica juncea), and lettuce (Lactuca sativa), at a depth of one-forth to one-half inch. As soon as the seeds were planted and the flats watered, the toxicant was sprayed on the soil as an acetone-water solution, at a rate equivalent to six pounds of toxicant per acre. Both the treated flats and an untreated control were held in the greenhouse for approximately three weeks, after which time the performance of the toxicant was assessed in terms of percent kill with respect to the untreated control. Results are presented in Table 1:

TABLE l.PRE-EMERGENCE HERBICIDAL ACTIVITY Test plant species: Percent kill Crabgrass 100 German hay millet 100 Yellow foxtail 100 Flax 100 Mustard 100 Lettuce 100 The post-emergence herbicidal activity of methyl-m- [(methylcarbamoyl)oxy]carbanilate was demonstrated as follows: In fiat pans was placed, to a depth of three inches, at 1:1 mixture of slit loam and sandy loam soil. In the soil were then planted seeds of corn (Zea mays), pea (Pisum sativum), peanut (Arachis hypogaea), cotton (Gossypium hirsutum), and soybean (Glycine max), at a depth of approximately one inch, and seeds of oats (Avena sativa), flax (Linum usitatissimum), mustard (Brassica juncea), lettuce (Lactuca sativa), tomato (Lycopersicum esculentum Mill.), pigweed (Amaranthus retroflexus), crabgrass (Digital-fa sanguinalis), barnyard grass (Echinochloa crusgalli), carrot (Daucus carota), cucumber (Cucumis sativus), safliower (Carthamus tinctoruis), at a depth of one-fourth to one-half inch. The flats were watered, and the seeds allowed to grow in the greenhouse for two weeks. Maintaining an untreated control, the stand of plants was then sprayed with a solution of methyl m-[(methylcarbamoyl)oxy]carbanilate in aqueous acetone, at the rate equivalent to six pounds of toxicant per acre. Both treated and untreated plants were held in the greenhouse for two to three weeks, after which the number of surviving plants were counted, and the percent kill with respect to the untreated control was determined.

Results are presented in Table 2 below.

TABLE 2.POST-EMERGENCE HERBICIDAL ACTIVITY Test plant species: Percent kill Corn Cats 0 Peanut 0 Cotton 80 Soybean 100 Flax 75 Mustard 100 Lettuce 100 Pea 0 Tomato 100 Pigweed 100 Crabgrass 20 Barnyard grass 0 Carrots 100 Cucumber 100 Safiiower 100 These results illustrate the effective action of the subject herbicide, in both pre-emergence and post-emergence application, against a broad spectrum of plant species.

In the following specific examples, which are given to further illustrate this invention, the pre-emergence and post-emergence herbicidal data reported for various plant species were obtained by the test methods described in Example 1.

Example 2.Methyl m-[(ethylcarbamoyl) oxy1carbanilate A mixture of 25.0 g. of methyl m-hydroxycarbanilate, 11.2 g. of ethyl isocyanate, and five drops of triethylamine was heated in a stoppered flask at 60 for three hours, cooled, and the crude product was recrystallized from ethyl acetate to yield 24.3 g. of solid melting at 146-50".

Recrystallization from toluene gave methyl m[(ethylcarbamoyl)oxy]carbanilate melting at 1567.

Analysis.Calculated for C H N O C, 55.45; H, 5.92; N, 11.76. Found: C, 55.57; H, 5.98; N, 11.52.

On pre-emergence testing of this compound 100% of mustard, lettuce, German hay millet, flax, crabgrass, and chickweed Were killed by a six pound per acre dosage.

In a post-emergence test, a dosage of six pounds per acre killed 100% of mustard, lettuce, and chickweed, 95% of fiax and crabgrass, and 75% of German hay millet.

Example 3.Methyl rn- (propylcarbamoyl) oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with propyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield methyl m-l(pr pylcarbamoyl)oxy]carbanilate melting at 148.59.5 after recrystallization from toluene.

AnaIysis.Calculated for C H N O C, 57.13; H, 6.39; N, 11.11. Found: C, 56.93; H, 6.31; N, 10.84.

A pre-emergence application of six pounds per acre of this compound killed 100% of mustard, lettuce, German hay millet, flax, crabgrass, and chickweed.

In a post-emergence test, 100% of mustard, lettuce, flax, crabgrass, and chickweed, and of German hay millet were killed by a six pound per acre dosage.

Example 4.-Methy1 m-[(isopropylcarbamoyl) oxy]carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with isopropyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield methyl m-[(isopropylcarbamoyl)oxy]carbanilate melting at 167-8 after recrystallization from toluene.

Analysis.--Calculated for C H N O C, 57.13; H, 6.39; N, 11.11. Found: C, 57.10; H, 6.46; N, 11.21.

In a pre-emergence test, a six pound per acre application resulted in 100% kill of mustard, lettuce, German hay millet, flax, crabgrass, and chickweed.

A dosage of six pounds per acre of this compound, applied post-emergently, killed 100% of mustard, lettuce, German hay millet, flax, and chickweed, and of crabgrass.

Example 5.Methyl m-[ (butylcarbamoyl) oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with butyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield methyl m-[(butylcarba moyl)oxy]carbanilate melting at 1178 after recrystallization from a benzene-hexane mixture.

Analysis.Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.85; H, 7.03; N, 10.81.

On pre-emergence testing of this compound, a six pound per acre dosage killed of mustard, lettuce, German hay millet, flax, barnyard grass, and chickweed.

In a post-emergency test, 100% of mustard, lettuce, German hay millet, crabgrass, and chickweed, and 95% of flax were killed by a six pound per acre application.

Example 6.-Methyl m-[(tert-butylcarbamoyl)oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with tert-butyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield methyl m-[(tert-butylcarbamoyl)oxy]carbanilate melting at 162-3 after recrystallization from ethyl acetate.

Analysis.Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.49; H, 6.66; N, 10.78.

In both pre-emergence and post-emergence applications, a dosage of six pounds per acre of this compound 9 killed 100% of mustard, lettuce, German hay millet, flax, crabgrass, and chickweed.

Example 7 .Methyl m-[ (isobutylcarb amoyl) oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with isobutyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield methyl m-[(isobutylcarbamoyl)oxy]carbanilate melting at l42-3 after recrystallization from aqueous methanol.

Analysis.Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.60; H, 6.97; N, 10.27.

In a pre-emergence test, an application of six pounds per acre killed 100% of mustard, lettuce, crabgrass, and pigweed, and 95% of flax.

On post-emergence testing of this compound, a dosage of six pounds per acre killed 100% of lettuce and carrots, 95% of mustard and crabgrass, and 80% of flax, with the surviving flax plants so severely injured that they were expected to die.

Example 8.Methyl m-[ sec-butylc arbamoyl) oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with sec-butyl isocyanate in the presence of 1,4-diazabicyclo[2.2.2]octane. The crude product was extracted with .cold 5% sodium hydroxide solution, and the remaining solid was recrystallized from benzene to yield methyl m-[(sec-butylcarbam- Example 9.Methyl m-[ (a'llylcarbamoyl) oxy] carbanilate Allyl isocyanate (16.4 g.) was added dropwise to a solution of 30.0 g. of methyl m-hydroxycarbanilate and 2.1 g. of 1,4-diazabicyclo[2.2.2] octane in 300 ml. of ethyl acetate. The reaction mixture was heated at 60 for three hours, cooled, and filtered to yield 35.7 g. of crude product. Recrystallization from ethyl acetate or from methanol gave methyl m-[(allylcar-bamoyl)oxy] carbanilate melting at 147-8".

Analysis.Calculated for C H N O C, 57.59; H, 5.64; N, 11.20. Found: C, 57.61; H, 5.74; N, 10.91.

In a pre-emergence test, 100% of mustard, lettuce, German hay millet, flax, crabgrass, and carrots were killed by a six pound per acre application of this compound.

A dosage of six pounds per acre, applied post-emergently, killed 100% of mustard, lettuce, German hay millet, crabgrass, and carrots, and 95 of flax.

Example 10.--Methyl N-methyl-m-[ (methylcarbamoyl) oxyJcarbanilate The intermediate methyl m hydroxy N methylcarbanilate was prepared as follows: Methyl chloroformate (14.2 g.) was added dropwise to a solution of 36.9 g. of m-(methylamino)phenol in 300 ml. of acetonitrile, maintaining the temperature at 25. When the addition was complete, the mixture was heated to 55, stirred at this temperature for 2.5 hours, and cooled to room temperature. The acetonitrile was removed under reduced pressure and the residual oil was dissolved by addition of 500 ml. of water and 500 ml. of ether. The aqueous layer was extracted with ether and the combined ether layers were washed with a 5% hydrochloric acid solution and with water. After drying the ether solution over magnesium sulfate, the ether was evaporated to yield 20 g. of light yellow oil. A small portion of this crude methyl m-hydroxy-N-methylcarbanilate was distilled to obtain an analytical sample boiling at (5x10 mm.).

Analysis-Calculated for C H N0 C, 59.66; H, 6.12; N, 7.73. Found: C, 59.76; -H, 6.24; N, 7.92.

' The crude methyl m-hydroxy-N-methylcarbanilate was reacted with methyl isocyanate as follows: Methyl isocyanate (5.0 g.) was added dropwise to a solution of 14.5 g. methyl m-hydroxy-N-methylcarbanilate and 20 drops of triethylamine in 150 ml. of benzene. The reaction mixture was stirred at room temperature for 1.5 hours and heated at 57 for three hours. The solvent was removed to yield 18.9 g. of crude methyl N-methyl-m-[(methylcarbamoyl)oxy] carbanilate, a yellow oil. A small portion of this oil was distilled to give an analytical sample boiling at (5 1()- mm.).

'Analysis.-Calculated for C H N O C, 55.45 H, 5.92; N, 11.76. Found: C, 55.35; H, 6.09; N, 11.81.

In a pre-emergence test, 100% of mustard, lettuce, flax, and crabgrass, of German hay millet, and 40% of barnyard grass were killed by a six pound per acre dosage of this compound.

On post-emergence testing, a six pound per acre dosage killed of lettuce and flax, and 25% of mustard (with the surviving plants severely injured and expected to die); there was slight to moderate damage to German hay millet, crabgrass, and barnyard grass.

Example 11.Methyl m-[(dimethylcarbamoyl)oxy] carbanilate The intermediate m-aminophenyl dimethylcarbamate was prepared as follows: m-Nitrophenol (100.0 g.) was added portionwise to a solution of 38.8 g. of sodium methoxide in 300 ml. of methanol, the solution was heated at 60-65 for 1.5 hour, then evaporated to dryness. This sodium salt of m-nitrophenol (111.0 g.) was dissolved in 700 ml. of dioxane, and 67.3 g. of dimethylcarbamoyl chloride was added dropwise over a one-half hour period. The reaction mixture was heated at 6065 for two hours, stirred overnight at room temperature, then poured into 3300 ml. of water. After stirring for one hour the crude m-nitrophenyl dimethylcarbamate (107.0 g., M.P. ,48-55") was isolated by filtration, and dissolved in 600 ml. of ethyl acetate. Platinum oxide (0.4 g.) was added and the mixture was hydrogenated in a Parr hydrogenation apparatus until the theoretical amount of hydrogen had been absorbed. The catalyst Was removed by filtration and the filtrate was concentrated to dryness. The residual yellow oil solidified on standing and was recrystallized from a benzene-petroleum ether mixture to yield 80.0 g. of m-aminophenyl dimethylcarbamate melting at 80-6.

This intermediate was reacted with methyl chloroformate as follows: To a solution of 9.9 g. of methyl chloroformate in 50 ml. of benzene, a solution of 18.0 g. of m-aminophenyl dimethylcarbamate and 10.1 g. of triethylamine in ml. of benzene was added dropwise, maintaining the temperature of the reaction at 2530. After the addition was complete, the mixture was stirred for one hour at 40 and for one hour at room temperature, then poured into 250 ml. of ether. The solid was collected by filtration, washed with water to remove the amine hydrochloride, yielding 11.9 g. of crude methyl m-[(dimethylcarbamoyl)oxy]carbanilate melting at l445. An additional 3.5 g. of product was obtained by concentration of the filtrate. Recrystallization from a benzene-hexane mixture raised the melting point to 145.0-5.5.

Analysin-Calculated for C H N O C, 55.45; H, 5.92; N, 11.76. Found: C, 55.57; H, 6.03; N, 11.79.

In a pre-emergence test, an application of six pounds per acre of this compound killed 100% of mustard, German hay millet, flax, and crabgrass, 90% of lettuce (with the surviving plants severely injured and expected to die), and 70% of barnyard grass.

1 1 A post-emergence application of six pounds per acre killed 100% or mustard, lettuce, German hay millet, flax, crabgrass, and barnyard grass.

Example 12.Methyl m-[(diethylcarbamoyl)oxy] carbanilate A suspension of 4.6 g. of sodium hydride in oil was added slowly to a solution of 16.7 g. of methyl m-hydroxycarbanilate in 50 ml. of N,N-dimethylformamide and 200 ml. of xylene, maintaining the temperature at 30-35. The mixture was stirred for one hour, then 13.6 g. of diethylcarbamoyl chloride was added dropwise, maintaining the temperature at 30-35". When the addition was complete, the reaction mixture was heated for one hour at 55-60, cooled, and the precipitate of sodium chloride removed by filtration. The filtrate was concentrated to dryness, the residue was washed with pentane, and triturated with water to give a crude solid product. After filtration and recrystallization from aqueous methanol, a

yield of 16.2 g. of methyl m-[(diethylcarbamoyl)oxy] Example 13.-Methyl m-[ (2-methylallyl) carbamoyl] oxy] carbanilate The intermediate chloroformate ester of methyl m hydroxycarbanilate was prepared as follows: Methyl mhydroxycarbanilate (33.4 g.) was converted to the sodium salt with sodium hydride as described in Example 12. This sodium salt was added portionwise to a solution of 19.8 g. of phosgene in 300 ml. of ethyl acetate, maintaining the temperature at 5 to 0. The mixture was stirred for one hour as it warmed to room temperature, then filtered to yield 44 g. of the chloroformate ester of methyl m-hydroxycarbanilate.

The intermediate was reacted with 2-methylallylamine as follows: Z-methylallylamine (28.4 g.) was added dropwise to a solution of 45.9 g. of the chloroformate ester of methyl m-hydroxycarbanil-ate in 300 ml. ofethyl acetate, maintaining the temperature at 30. The mixture was stirred for one hour and allowed to stand overnight. The precipitate of amine hydrochloride was removed by filtration and the filtrate was concentrated to dryness. The crude methyl m-[ (Z-methylallyl carbamoyl] oxy] carbanilate was recrystallized several times from a benzenehexane mixture to obtain a sample melting at 127.5-8.5.

Analysis.Calculated for C H N O.,: C, 59.08; H, 6.10; N, 10.60. Found: C, 59.29; H, 6.27; N, 10.78.

In a pre-emergence test, 100% of mustard, German hay millet, flax, and crabgrass, 95% of barnyard grass, and 90% of lettuce were killed by a six pound per acre dosage.

A post-emergence application of six pounds per acre of this compound killed 100% of mustard, lettuce, German hay millet, flax, crabgrass, and barnyard grass.

Example 14.--Sec-butyl m[(dimethylcarbamoyl)oxy] carbanilate The intermediate m-aminophenyl dimethylcarbamate (Ex. 11) was reacted with sec-butyl chlorofortrnate as follows: A solution of 18.0 g. of m-aminophenyl dimethylcarbamate and 10.1 g. of triethylamine in 200 ml. of benzene was added to a solution of 14.3 g. of sec-butyl chloroformate in 50 ml. of benzene, maintaining the temperature at 2530. The mixture was stirred for one hour at 45-50, and allowed to stand over the weekend. The amine hydrochloride was removed by filtration and the filtrate was concentrated to dryness. The residual oil was dissolved in ether and the ether layer was washed with a cold 5% solution of hydrochloric acid and with water. After drying the solution over magnesium sulfate, the ether was removed to give a red oil which crystallized on standing. After recrystallization from a benzene-hexane mixture, a yield of 13.5 g. of sec-butyl m-[(dimethylcarbamoyl)oxy]carbanilate, melting at 92.5-4.0, was obtained.

Analysis.Calculated for C H N O C, 59.98; H, 7.19; N, 9.99. Found: C, 59.94; H, 7.06; N, 10.13.

A dosage of six pounds per acre of this compound, applied pre-emergently, caused 100% kill of mustard and flax, kill of crabgrass, 90% kill of lettuce and German hay millet, and moderate damage to barnyard grass.

On post-emergence testing, of mustard, lettuce, and flax, and 90% of German hay millet were killed by a six pound per acre application. Crabgrass and barnyarn grass were moderately injured.

Example 15.S-methyl m-[(methylcarbamoyl)oxy] thiocarbanilate The intermediate S-methyl m-hydroxythiocarbanilate was prepared as follows: A solution of 43.6 g. of m-aminophenol in 300 ml. of acetonitrile was warmed to 35, and 22.0 g. of S-methyl chlorothioformate was added dropwise. The temperature of the mixture rose to 55. The mixture was stirred for two hours at 70, cooled to room temperature, and the precipitate (m-aminophenol hydrochloride) was removed by filtration. Concentration of the filtrate gave 36.1 g. of crude S-methyl m-hydroxythiocarbanilate melting at 9. Two recrystallizations from aqueous methanol raised the melting point to 139- 40.

Analysis.-Calculated for C H NO S: C, 52.44; H, 4.95; N, 7.65. Found: C, 52.31; H, 5.07; N, 7.52.

This product was reacted with methyl isocyanate as follows: Methyl isocyanate (4.85 g.) was added dropwise to a stirred suspension of 15.5 g. of S-methyl m-hydroxythiocarbanilate and 25 drops of triethylamine in ml. of benzene. When the addition was complete, the mixture was heated to 70 for two hours, then cooled. The crude product was isolated by filtration and recrystallized from aqueous methanol to yield 13.4 g. of white crystals melting at 153-8. A second recrystallization of the S-methyl m-[ (methylcarbamoyl) oxy] thiocarbanilate produced a sample melting at 153.5- 4.5.

Analysis.-Calculated for C H N O S: C, 49.98; H, 5.03; N, 11.66. Found: C, 49.71; H, 4.77; N, 11.79.

A pre-emergence application of six pounds per acre of this compound killed 100% of mustard, German hay millet, flax, crabgrass, and barnyard grass, and 80% of lettuce, with the surviving plants so severely injured they were almost certain to die.

In a post-emergence test, 100% of mustard, lettuce, German hay millet, flax, crabgrass, and barnyard grass were killed by a six pound per acre dosage.

Example 16.Is0propyl m-[ (methylcarbamoyl) oxy] carbanilate Example 17.Methyl m-[(cyclohexylcarbamoyl) oxy]carbanilate Cyclohexyl isocyanate (11.8 g.) was added dropwise to a solution of 15.0 g. of methyl m-hydroxycarbanilate i 13 and 1.1 g. of 1,4-diazabicyclo[2.2.2]octane in 150 ml. of benzene. The mixture was refluxed for one hour, cooled, and filtered. The white solid was recrystallized several times from aqueous methanol to yield 14.0 g. of methyl m [(cyclohexylcarbamoyl)oxy]carbanilate melting at 166-7".

Analysis.--Calculated for C H bN O C, 61.63; H, 6.90; N, 9.58. Found: C, 61.83;-H, 7.13; N, 9.83.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 18.Methyl m- (Phenylcarbamoy1)oxy] carbanilate Following the procedure described in Example 2, methyl m-hydroxycarbanilate was reacted with phenyl isocyanate, in the presence of 1,4-diazabicy clo[2.2.2]octane, to yield methyl m-[(phenylcarbamoyl)oxy]carbanilate. The crude product was dissolved in ethyl acetate, washed with a cold 5% solution of sodium hydroxide, and concentrated to dryness. The white solid melted at 1545 after recrystallization from benzene.

Analysis.Calculated for C H N' O C, 62.93; H, 4.93; N, 9.79. Found: C, 62.72; H, 4.97; N, 9.63.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 19.-Allyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate allyl m-hydroxycarbanilate was prepared from m-aminophenol and allyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate. The crude product was dissolved in ether and extracted with dilute hydrochloric acid and with water. The ether solution was Example 20.-Allyl m-[(tert-butylcarbamoyl)oxy] carbanilate Following the procedure described in Example 2, allyl m-hydroxycarbanilate was reacted with tert-butyl isocyanate, in the presence of 1,4-diazabicyclo[2.2.2]octane, to yield allyl m-[(tert-butylcarbamoyl)oxy]carbanilate melting at 155-6 after recrystallization from aqueous methanol.

Anulysis.Calculated for C H N O C, 61.63; H, 6.90; N, 9.58. Found: C, 61.91; H, 6.98; N, 9.58.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 21.Ethyl m-[(methylcarbam0yl)oxy] carbanilate The intermediate ethyl m-hydroxycarbanilate (M.P. 9780) was prepared from m-aminophenol and ethyl chloroformate followingv the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.-Calculated for C H NO C, 59.66; H, 6.12; N, 7.73. Found: C, 59.67; H, 6.28; N, 7.61.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example. 17, to yield ethyl m-[(methylcarbamoyl)oxy]carbanilate melting at 1367 after recrystallization from toluene.

Analysis.Calculated for C H N O C, 55.45; H, 5.92; N, 11.76. Found: C, 55.60; H, 5.62; N, 11.58.

The compoundshowed herbicidal activity at a dosage of 6 pounds per acre.

Example 22.Propyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate propyl m-hydroxycarbanilate (M.P. 72.03.5) was prepared from m-aminophenol and propyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.-Calculated for C H NO C, 61.52; H, 6.71; N, 7.18. Found: C, 61.73; H, 6.66; N, 7.21.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 17, to yield propyl m-[(methylcarbamoyl)oxy]carbanilate melting at 128.530.0 after recrystallization from toluene.

Analysis.Calculated for C H N O C, 57.13; H,

6.39; N, 11.11. Found: C, 57.34; H, 6.49; N. 10.92.

The compound showed herbicidal activity at' a dosage of 6 pounds per acre.

Example 23.Butyl m-[(methylcarbamoyDoxyjcarbanilate The intermediate butyl m-hydroxycarbanilate (M.P. 87-8) was prepared from m-aminophenol and butyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.Calculated for C H NO C, 63.14; H, 7.23; N, 6.69. Found: C, 62.89; H, 7.39; N, 6.78.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 17, to yield butyl 'm-[(methylcarbamoyl)oxy]carbanilate melting at 113.5-45 after recrystallization from benzene.

Analysis.Calculated for C H N O C, 58.63, H,

6.81; N, 10.52. Found: C, 58.37; H, 6.61; N, 10.38.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 24.-Isobutyl m-[ (methylcarbamoy1)oxy]carbanilate .The intermediate isobutyl m-hydroxycarbanilate (M.P. 106.58.0) was prepared from m-aminophenol and isobutyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.-Calculated for C H NO C, 63.14; H, 7.23; N, 6.69. Found: C, 63.40; H, 7.24; N, 6.74.

This intermediate was reacted with methyl isocyanate,

following the procedure described in Example 17, to yield isobutyl m-[(methylcarbamoyl)oxy]carbanilate melting at 133-4 after recrystallization from benzene.

Analysis.--Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.82; H, 6.58; N, 10.34.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 25 .Sec-butyl m-[ (methylcarbamoyl)oxy]carbanilate The intermediate sec-butyl m-hydroxycarbanilate (M.P. 117.58.5) was prepared from m-aminophenol and secbutyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.Calculated for C H NO C, 63.14; H, 7.23; N, 6.69. Found: C, 63.38; H, 7.19; N, 6.50.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 17, to yield sec-butyl m-[(methylcarbamoyl)oxy]carbanilate melting at 126.5-7.5 after recrystallization from benzene.

Analysis.Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.88; H, 6.99; N, 10.50.

15 The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 26.Tert-butyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate tert-butyl m-hydroxycarbanilate was prepared as follows: A solution of m-aminophenol in 450 ml. of acetonitrile was added dropwise to a stirred solution of 54.6 g. of tert-butyl chloroformate in 200 ml. of acetonitrile, maintaining the temperature of the reaction mixture below When the addition was complete, the mixture was allowed to warm to room temperature, stirred for three hours, and allowed to stand for 48 hours. The mixture was filtered to remove the m-aminophenol hydrochloride, and the filtrate was concentrated to dryness. The residue was extracted with ether, the insoluble m-aminophenol was removed, and the ether solution was extracted with cold hydrochloric acid solution and with water. The ether layer was dried over magnesium sulfate, evaporated to dryness and the residual solid recrystallized from aqueous methanol to yield 13.5 g. of tert-butyl m-hydroxycarbanilate melting at 135.05.5.

Analysis.Calculated for C H NO C, 63.14; H, 7.23; N, 6.69. Found: C, 62.99; H, 7.48; N, 6.90.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 17, to yield tert-butyl rn-[(methylcarbamoyl)oxy1carbanilate, melting at 157-8".

Analysis-Calculated for C H N O C, 58.63; H, 6.81; N, 10.52. Found: C, 58.65; H, 6.70; N, 10.76.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 27.Sec-butyl m-[(tert-butylcarbamoyl)oxy] carbanilate Following the procedure described in Example 2, secbutyl m-hydroxycarbanilate was reacted with tert-butyl isocyanate to yield sec-butyl m[(tert-butylcarbamoyl)- oxy]carbanilate melting at 140.040.5 after recrystallization from a benzene-hexane mixture.

Analysis.-Calculated for C H N O C, 62.31; H, 7.85; N, 9.09. Found: C, 62.52; H, 7.96; N, 9.20.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 28.-Methyl m-[(hexylcarbamoyl)oxy]carbanilate Hexyl isocyanate (13.4 g.) was added dropwise to a stirred solution of 16.7 g. of methyl m-hydroxycarbanilate and 25 drops of triethylamine in 200 ml. of benzene, and the reaction mixture was stirred for nine hours at room temperature. The crude methyl m-[(hexylcarbamoyl)- oxy]carbanilate was isolated by filtration and recrystallized from aqueous methanol to yield 24.2 g. of pure product melting at 115.56.5.

Analysis.-Calculated for C H N O C, 61.20; H, 7.53; N, 9.52. Found: C, 61.19; H, 7.40; N, 9.27.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 29.Methyl m-[[(1,1,3,3-tetramethylbutyl) carbamoyl]oxy]carbanilate The reactants, 12.5 g. of methyl m-hydroxycarbanilate, 1.0 g. of l,4-diazabicyclo[2.2.2]octane, and 12.3 g. of 1,1,3,3-tetramethylbutyl isocyanate, were mixed by hand, and the mixture was heated in a stoppered flask at 60 for eight hours. Hexane (100 ml.) was added, the mixture was filtered, and the crude solid product was dissolved in 500 ml. of ethylacetate and 100 ml. of ether. The solution was washed with a cold 5% solution of sodium hydroxide and with water, dried over magnesium sulfate, and concentrated to dryness. The residue was recrystallized from aqueous methanol to yield 10.0 g. of methyl m [[(1,1,3,3-tetramethylbutyl)carbamoyl]oxy] carbanilate, melting at ISO-1. A second recrystallization 16 from aqueous methanol raised the melting point to 152.02.5.

Analysis.-Calculated for C H N O C, 63.33; H, 8.13; N, 8.69. Found: C, 63.57; H, 7.89; N, 8.73.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 30.Allyl m-[(allylcarbamoyl)oxy] carbanilate Following the procedure described in Example 28, allyl m-hydroxycarbanilate was reacted with allyl isocyanate to yield allyl m-[ (allylcarbamoyl)oxy]carbani1ate melting at 105.5-6.0 after recrystallization from aqueous methanol.

Analysis.-Calculated for C H N O C, 60.86; H, 5.83; N, 10.14. Found: C, 60.59; H, 6.03; N, 9.95.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 3 1.-Sec-butyl-m-[ (isopropylcarbamoyl)oxy] carbanilate Following the procedure described in Example 17, secbutyl m-hydroxycarbanilate was reacted with isopropyl isocyanate, in the presence of triethylamine, to yield secbutyl m-[(isopropylcarbamoyl)oxylcarbanilate melting at l51.52.0 after recrystallization from aqueous methanol.

Analysis.-Calculated for C H N O C, 61.20; H, 7.53; N, 9.52. Found: C, 61.20; H, 7.73; N, 9.68.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 32.-Pentyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate pentyl m-hydroxycarbanilate was prepared as follows: Pentyl chloroformate (30.1 g.) was added dropwise to a solution of 43.6 g. of m-aminophenol in 300 ml. of acetonitrile. The reaction was exothermic and the temperature had risen to 42 by the time the addition was complete. The reaction mixture was heated to 76, maintained at that temperature for one hour, then allowed to cool to room temperature. The mixture was poured into ice water and the water extracted with ether. The ether solution was washed with 10% hydrochloric acid solution and with water, dried over magnesium sulfate and concentrated to dryness. The residual solid was recrystallized from .a benzene-hexane mixture to yield 28.7 g. of pentyl m-hydroxycarbanilate melting at 80.0- 81.5 Further recrystallization from benzene raised the melting point to 82.5-3.0.

Analysis.-Calculated for C H NO C, 64.55; H, 7.68; N, 6.27. Found: C, 64.66; H, 7.38; N, 6.50.

This intermediate was reacted with methyl isocyanate as follows: Methyl isocyanate (4.9 g.) was added dropwise to a stirred mixture of 16.7 g. of pentyl m-hydroxycarbanilate and 25 drops of triethylamine in 200 ml. of benzene. When the addition was complete, the solution was heated to 65 and maintained at this temperature for two hours, then allowed to cool. The white solid was collected by filtration and recrystallized from aqueous methanol to yield 17.3 g. of pentyl m-[ (methylcarbamoyl)oxy] carbanilate melting at 106.57.5

Analysis.-Calculated for C H N O C, 59.98; H, 7.19; N, 9.99. Found: C, 60.19; H, 7.09; N, 10.19.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 33.1-methylbutyl m (methylcarbamoyl) oxy] carbanilate The intermediate l-methylbutyl m-hydroxycarbanilate (MP. 86.57.0) was prepared from m-aminophenol and l-methylbutyl chloroformate following the procedure described in Example 32 for the preparation of pentyl m-hydroxycarbanilate.

Example 34.-1-ethylpropyl m-[(rnethylcarbamoyl)oxy] carbanilate The intermediate l-ethylpropyl m-hydroxycarbanilate (M.P. 108.5-9.5) was prepared from m-aminophenol and l-ethylpropyl chloroformate following the procedure described in Example 1 for the preparation of methyl mhydroxycarbanilate.

Analysis.-Calculated for C H NO C, 64.55; H, 7.68; N, 6.27. Found: C, 64.69; H, 7.52; N, 6.53.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 32, to yield 1 ethylpropyl m [(methylcarbamoyl)oxyJcarbanilate melting at 129-30 after recrystallization from aqueous methanol.

Analysis-Calculated for C H N O C, 59.98; H, 7.19; N, 9.99. Found: C, 59.85; H, 7.26; N, 9.88.

The compound showed herbicidal activity .at a dosage of 6 pounds per acre.

Example 35 .1,2-dimethylpropyl m-[(methylcarbamoyl) oxy] carbanilate The intermediate 1,2 dimethylpropyl m hydroxycarbanilate (M.P. 137-8) was prepared from m-aminophenol and 1,2-dimethylpropyl chloroformate following the procedure described in Example 1 for the preparation of methyl m-hydroxycarbanilate.

Analysis.-Calculated for C12H17NO3I C, 64.55; H, 7.68; N, 6.27. Found: C, 64.36; H, 7.50; N, 6.46.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 32, to yield 1,2 dimethylpropyl m [(methylcarbamoyl)oxy] carbanilate melting at 143-4 .after recrystallization from aqueous methanol.

Analysis.Calculated for C I-1 N C, 59.98; H, 7.19; N, 9.99. Found: C, 60.00; H, 7.14; N, 9.85.

The compound showed'herbicidal activity at a dosage of 6 pounds per acre.

Example 36.2-methylallyl m-[(-methylcarbamoyl) oxy]- carbanilate The intermediate Z-methylallyl m-hydroxycarbanilate was prepared as follows: 2-methylallyl chloroformate (26.8 g.) was added dropwise to a solution of 43.6 g. of m-aminophenol in 300 ml. of acetonitrile. The temperature rose to 62 during the addition and a solid settled out of the solution. The slurry was heated at 70 for two hours, cooled to room temperature, and filtered. The filtrate was concentrated to dryness, the residual oil was dissolved in benzene, and the benzene solution was washed with 10% hydrochloric acid solution and with water. After drying the solution over magnesium sulfate, the benzene was removed under reduced pressure, to yield a brown oil which crystallized on standing. Recrystallization from a benzene-petroleum ether mixture produced 17.3 g. of 2-methylallyl im-hydroxycarbanilate melting at 66-7 A second recrystallization from the same solvent raised the melting point to 689.

Analysis-Calculated for C H NO C, 63.75; H, 6.32; N, 6.76. Found: C, 64.04; H, 6.49; N, 7.03.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 32, to yield 2-methylally1 rn-[ (methylcarb amoyl) oxy] carbanilate melting at 126-7 after recrystallization from aqueous methanol.

18 Analysir-Calculated for C H N O C, 59.08; H, 6.10; N, 10.60. Found: C, 58.83; H, 6.34; N, 10.83.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 37.-2-propynyl m-[(methylc-arbamoyl)oxy]- carbanilate The intermediate 2-propynyl m-hydroxycarbanilate (M.P. 83.0-4.5) was prepared from m-aminophenol and 2-propynyl chloroformate following the procedure described in Example 36 for the preparation of 2-methylallyl m-hydroxycarbanilate.

Analysis-Calculated for C H NO C, 62.82; H, 4.75; N, 7.33. Found: C, 63.06; H, 4.76; N, 7.41.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 32, to yield 2-propynyl m-[(methylcarbamoyl)oxy]carbanilate melting at 128-9 after recrystallization from aqueous methanol.

Analysis-Calculated for C H N O C, 58.06; H, 4.87; N, 11.29. Found: C, 57.78; H, 5. 06; N, 11.49.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 38.Methyl m-[(dimethylcarbamoyl)oxy]-N- methylcarbanilate A suspension of 4.0 g. of sodium hydride in oil was added portionwise to a solution of 15.5 g. of methyl mhydroxy-N-methylcarbanilate in 40 ml. of N,N-dimethylformamide and 160ml. of xylene. The mixture was stirred at 55-60 for one hour, cooled to 22, and 9.3 g. of dimethylcarbamoyl chloride was added dropwise over a 15 minute period. The reaction mixture was stirred at room temperature overnight, then filtered to remove the precipitate of sodium chloride. The filtrate was evaporated to dryness, the residual oil dissolved in ether, and the ether solution washed with a cold 5% solution of sodium hydroxide and with water. After drying over magnesium sulfate, the ether was removed and the residual semi-solid was thoroughly washed with pentane to remove the oil. The crude product was recrystallized from a benzene-hexane mixture to yield methyl rn-[(dimethylcarbamoyl)oxy]-N-methylcarbanilate melting at 713. A small portion was sublimed at (0.01 mm.) to give an analytical sample melting at 78-9".

Analysis-Calculated for C H N O C, 57.13; H, 6.39; N, 11.11. Found: C, 57.22; H, 6.63; N, 11.28.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 39.Methyl m-[(diisopropylcarbamoyl)oxy]- carbanilate Following the procedure described in Example 38, methyl m-hydroxycarbanilate was converted to the sodium salt with sodium hydride, and this sodium salt was reacted with diisopropylcarbamoyl chloride to yield methyl m-[ (diisopropylcarbamoyl) oxy]-carbanilate melting at 113-4 after recrystallization from a benzenehexane mixture.

Analysis.Calculated for C H N O C, 61.20; H, 7.53; N. 9.52. Found: C, 61.27; H, 7.69; N, 9.57.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 40.Methyl m-[(butylmethylcarbamoyl)oxy]- carbanilate Following the procedure described in Example 38, methyl m-hydroxycarbanilate was converted to the sodium salt with sodium hydride, and this sodium salt was reacted with butylmethylcarbamoyl chloride to yield methyl m-[(butylmethylcarbamoyl)oxy]carbanilate melting at 86-8". A small portion was distilled at (0.025 mm.) to give an analytical sample.

Analysis.Calculated for C I-1 N 0 C, 59.98; H, 7.19; N, 9.99. Found: C, 60.03; H, 7.12; N, 9.78.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 41.Sec butyl m-[(diethylcarbamoyl)oxy]- carbanilate Following the procedure described in Example 38, secbutyl m-hydroxycarbanilate was converted to the sodium salt with sodium hydride, and this sodium salt was reacted with diethylcarbamoyl chloride to yield sec-butyl m[(diethylcarbamoyl)oxy]c-arbanilate melting at 58-60". A small portion was distilled at 135 (0.025 mm.) to give an analytical sample.

Analysis-Calculated for C H N O C, 62.31; H, 7.85; N, 9.09. Found: C, 62.32; H, 7.74; N, 9.24.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 42.S-ethyl m-[(methylcarbamoyl)oxy]- thiocarbanilate The intermediate S-ethyl m-hydroxythiocar-banilate (MP. 79-80) was prepared from m-aminophenol and S-ethyl chlorothioformate following the procedure described in Example 15 for the preparation of S-methyl m-hydroxythiocarbanilate.

Analysis.-Calculated for C H NO S: C, 54.79; H, 5.62; N, 7.10. Found: C, 54.85; H, 5.39; N, 7.36.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 15, to yield S-ethyl m-[(methylcarbamoyl)oxy]thiocarbanilate melting at 154-5 after recrystallization from aqueous methanol.

Analysis.-Calculated for C H N O S: C, 51.94; H, 5.50; N, 11.01. Found: C, 51.82; H, 5.37; N, 11.18.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 43.Methyl m-[[(m-chlorophenyl)carbamoyl] oxy] carb anilate Following the procedure described in Example 17, methyl m-hydroxycarbanilate was reacted with m-chlorophenyl isocyanate to yield methyl m-[[(m-chlorophenyl) carbamoyl]oxy]carbanilate melting at 159-61 after recrystallization from methanol.

Analysis.-Calculated for C H CIN O C, 56.17; H, 4.09; N, 8.73. Found: C, 55.90; H, 3.88; N, 8.52.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 44.-Cyclohexyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate cyclohexyl m-hydroxycarbanilate was prepared as follows: Cyclohexyl chloroformate (60.2 g.) was added dropwise to a solution of 87.3 g. of m-aminophenol in 700 ml. of acetonitrile, maintaining the temperature below 32. When the addition was complete, the mixture was refluxed for two hours, cooled, and filtered. The solid was washed with water to remove the amine hydrochloride, leaving 61.4 g. of crude product. An additional 17.1 g. of product were obtained by evaporation of the filtrate. The combined samples were recrystallized from aqueous methanol, and from an ethyl acetate-toluene mixture, to yield 52.6 g. of cyclohexyl m-hydroxycarbanilate melting at l7980.

Analysis-Calculated for C H NO C, 66.36; H, 7.28; N, 5.95. Found: C, 66.43; H, 7.32; N, 6.16.

This intermediate was reacted with methyl isocyanate as follows: Methyl isocyanate (9.0 g.) was added dropwise to a solution of 35.3 g. of cyclohexyl m-hydroxycarbanilate and six drops of triethylamine in 300 ml. of ethyl acetate. The mixture was refluxed for one hour, then concentrated to dryness. A yield of 20.9 g. of cyclohexyl m-[(methylcarbamoyl)oxy]carbanilate was obtained by recrystallization of the crude product from aqueous methanol and from ethyl acetate.

20 Analysis.--Calculated for C H N O C, 61.63; H, 6.90; N, 9.58. Found: C, 61.74; H, 7.17; N, 9.46.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 45 .Phenyl m- (methylcarbamoyl)oxy] carbanilate The intermediate phenyl m-hydroxycarbanilate (M.P. 180.08l.5) was prepared from m-aminophenol and phenyl chloroformate following the procedure described in Example 44 for the preparation of cyclohexyl m-hydroxy carbanilate.

Analysis.Calculated for C H NO C, 68.11; H, 4.84; N, 6.11. Found: C, 68.04; H, 5.00; N, 6.00.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 17, to yield phenyl m-[(methylcarbamoyl)oxy]carbanilate melting at 163.03.5 after recrystallization from aqueous methanol.

Analysis.-Calculated for C H N O C, 62.93; H, 4.93; N, 9.79. Found: C, 63.07; H, 4.99; N, 9.52.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 46.-2-methoxyethyl m-[(methylcarbamoyl) oxy] carbanilate The intermediate 2-methoxyethyl m-hydroxycarbanilate (M.P. 703) was prepared from m-aminophenol and 2- methoxyethyl chloroformate following the procedure described in Example 36 for the preparation of 2-methylallyl m-hydroxycarbanilate.

Analysis.Calculated for C H NO C, 56.86; H, 6.20; N, 6.63. Found: C, 57.14; H, 6.36; N, 6.39.

This intermediate was reacted with methyl isocyanate, following the procedure described in Example 32, to yield 2 methoxyethyl m-[(methylcarbamoyl)oxy]carbanilate melting at 845 after recrystallization from aqueous methanol.

Analysis-Calculated for C I-1 N 0 C, 53.72; H, 6.01; N, 10.44. Found: C, 53.67; H, 5.82; N, 10.66.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Example 47.Benzyl m-[(methylcarbamoyl)oxy] carbanilate The intermediate benzyl m-hydroxycarbanilate was prepared as follows: Benzyl chloroformate (34.1 g.) was added dropwise to a stirred solution of 43.6 g. of maminophenol in 300 ml. of acetonitrile. The temperature, which rose to 40 during the addition, was increased to 5560 and maintained there for two hours. After cooling, the mixture was poured into 1200 ml. of ice-water, the suspension was stirred for one hour, and the crude product was collected by filtration and recrystallized from a benzene-hexane mixture. A yield of 37.1 g. of benzyl m-hydroxycarbanilate, melting at 1267 was obtained. A second recrystallization from benzene raised the melting point to 127.58.0.

Analysis.Calculated for C H NO C, 69.12; H, 5.39; N. 5.76. Found: C, 68.90; H, 5.09; N, 6.02.

This intermediate was reacted with methyl isocyanate, following the procedures described in Example 32, to yield benzyl m-[(methylcarbamoyl)oxy1carbanilate melting at 1200-205 after recrystallization from aqueous methanol.

Analysis.-Calculated for C H N O C, 63.99; H, 5.37; N, 9.33. Found: C, 64.20; H, 5.12; N, 9.20.

The compound showed herbicidal activity at a dosage of 6 pounds per acre.

Other examples of compounds falling within the generic formulas presented herein, which may be formulated into herbicidal compositions and applied as herein illustrated are:

methyl-m[ (cyclopropylcarb amoyl oxy] carbanilate ethyl m- (tert-butylcarbamoyl oxy] carbanilate cyclopropyl m- (isopropylcarbamoyl) oxy] carbanilate propyl m[ tert-butylcarbamoyl) oxy] carbanilate butyl m[ (tert-butylcarbamoyl) oxy] carbanilate methyl m[ (neopentylcarbamoyl) oxy] carbanilate methyl m[ (tert-butylcarbamoyl) oxy] -N-methylcarbanilate methyl m- (p peridinocarbonyl oxy] carbanilate methyl mtert-butylmethylcarbamoyl oxy] carbanilate ethyl m- (ethylisopropylcarbamoyl oxy] carbanilate S-methyl m- (tert-butylcarbamoyl oxy] thiocarbanilate methyl N-ethyl-m- (methylcarbamoyl) oxy] carbanilate S-methyl m[ (isopropylcarb amoyl) oxy] thiocarbanilate ethyl m[ (Z-methylallyl carbamoyl] oxy] carbanilate It is clear that the classes of m-(carbamoyloxy)carbanilate esters described and illustrated herein are characterized by herbicidal activity, and that the degree of this activity varies among specific compounds within these classes and to some extent among the species of plant to which these compounds may be applied. Thus, selection of a specific herbicidal compound to control undesirable plant species without injury to a desired crop species may readily be made.

The active herbicidal compounds of this invention may be formulated and/or applied with insecticides, fungicides, nematocides, plant growth regulators, fertilizers, and other agricultural chemicals and may be used as effective soil sterilants as Well as in herbicidal applications. In applying an active compound of this invention, whether formulated alone or with other agricultural chemicals, an effective amount and concentration of the m-[(N-substituted-carbamoyDoxy] carbanilate ester is of course employed.

It is apparent that various modifications may be made in the formulation and application of the novel compounds of this invention, without departing from the inventive concept herein, as defined in the following claims.

We claim:

1. Novel chemical compounds of the formula wherein R is the radical of an aliphatic or cycloalkyl is the radical of a primary or secondary amine of the formula where R and R are hydrocarbon or monochlorohydrocarbon or hydrocarbon containing an ether oxygen or R is hydrogen,

is the radical of an m-arninophenol of the formula OH [ja RD R is hydrogen or a methyl group and X is oxygen or sulfur, none of said R R or R having over eight carbon atoms.

2. Compounds as set forth in claim 1 in which R is an aliphatic hydrocarbon radical.

3. Compounds as set forth in claim 1 in which R R R and R contain only carbon and hydrogen.

4. Compounds as set forth in claim 1 in which R is a hydrocarbon radical and R is hydrogen or a hydrocarbon radical and R is hydrogen or methyl.

5. Compounds as set forth in claim 4 in which any hydrocarbon radicals of R and R are aliphatic and the sum of the lengths of the longest straight chain, or single carbon, of the R substituent and the longest straight chain, or single carbon, of any R substituent is at most four carbon atoms.

6. Compounds as set forth in claim 4 in which R is an aliphatic hydrocarbon radical of one to four carbon atoms and X is oxygen.

7. Compounds as set forth in claim 4 in which R is an aliphatic hydrocarbon radical of less than three carbon atoms and X is sulfur.

8. Compounds as set forth in claim 5 in which R is alkyl of one to four carbons and X is oxygen.

9. Compounds as set forth in claim 5 in which R is alkyl of less than three carbon atoms and X is sulfur.

10. Compounds as set forth in claim 6 in which R is alkyl.

11. Compounds as set forth in claim 5 in which R is methyl.

12. Compound as set forth in claim 1 on the formula methyl m[ (methylcarbamoyl) oxy] carbanilate.

13. Compound as set forth in claim 1 of the formula methyl m[ (isopropylcarbamoyl oxy] carb anilate.

14. Compound as set forth in claim 1 of the formula methyl m (tert-butylcarbamoyl) oxy] carbanilate.

15. Herbicidal compositions comprising as an essential active ingredient an effective herbicidal amount of a compound of the formula wherein R is the radical of an aliphatic or cycloalkyl alcohol of the formula R OH or a phenol of the formula R OH,

is the radical of a primary or secondary amine of the formula carbon or hydrocarbon containing an ether oxygen or R is hydrogen,

23 is the radical of an m-aminophenol of the formula R is hydrogen or a methyl group and X is oxygen or sulfur, none ofsaid R R or R having over eight carbon atoms.

16. Herbicidal compositions comprising as an essential active ingredient an effective herbicidal amount of a compound as set forth in claim 15 in which R R R and R contain only carbon and hydrogen.

17. Herbicidal compositions as in claim 16 in which R and R are hydrogen.

18. Method of controlling undesired plant growth which comprises applying to the locus wherein control is desired a herbicidal amount of a compound of the formula wherein R is the radical of an aliphatic or cycloalkyl alcohol of the formula R OH or a phenol of the formula R OH,

Re is the radical of a primary or secondary amine of the formula where R and R are hydrocarbon or monochlorohydrocarbon or hydrocarbon containing an ether oxygen or R is hydrogen,

24 is the radical of an m-aminophenol of the formula NII R is hydrogen or a methyl group and X is oxygen or sulfur, none of said R R or R having over eight carbon atoms.

19. Method as set forth in claim 18 in which R is an aliphatic hydrocarbon radical.

20. Method as set forth in claim 18 in which R R R and R contain only carbon and hydrogen.

21. Method as set forth in claim 18 in which R is an aliphatic hydrocarbon radical of less than three carbon atoms, R is a hydrocarbon radical, R is hydrogen or a hydrocarbon radical, R is hydrogen or methyl, and X is sulfur.

22. Method as set forth in claim 21 in which any hydrocarbon radicals of R and R are aliphatic and R is alkyl of one to four carbons; the sum of the lengths of the longest straight chain or single carbon of the R substituent, and the longest straight chain or single carbon of any R substituent, is at most four carbon atoms; and X is oxygen.

23. Method as set forth in claim 22 in which R is methyl.

24. Method as set forth in claim 18 in which the compound is of the formula methyl m-((isopropylcarbam0yl) oxy) -carbanilate.

25. Method as set forth in claim 18 in which the compound is of the formula methyl m-((tert-butylcarbamoyl) oxy)-carbanilate.

References Cited UNITED STATES PATENTS 2,362,308 11/1944 Stevens et al. 260-479 2,978,310 4/1961 Daams et al. 712.3 3,037,993 6/1962 Shulgin 712.6 XR

OTHER REFERENCES Weizman et al.: JOC 13, pp. 796-799, 1948.

Derwent: French Patent Abstracts, vol. 8, No. 1, Jan. 8, 1968. S. Afr., 67/4,310, Algicidcs. General Organic, p. 6.

LEWIS GOTTS, Primary Examiner.

G. HOLLRAH, Assistant Examiner. 

